Substance abusers, and the methadone maintained in particular, smoke at exceptionally high rates, and hence experience disproportionately high risks for cancer. Although the methadone maintained express substantial interest in smoking cessation, effective interventions are still lacking. Previous research suggests that illicit substance use plays an important role in tobacco smoking for this group, but how this affects smoking cessation outcomes is not known. This project seeks to conduct secondary analyses, to determine predictors of outcome, on the first large scale (N=180) dataset on smoking cessation interventions for methadone maintained opiate abusers. The NIDA funded parent project which provides the basis for this proposal evaluated the efficacy of relapse prevention and contingency management for enhancing nicotine patch treatment outcomes in the methadone maintained. Secondary data analysis will be broken into two primary strategies: (1) Discriminant function analysis will be used to identify predictors of smoking cessation outcome during treatment, at the end of treatment, and at 6- and 12-month follow-up. (2) Latent growth models will be used to examine the causal relationship between tobacco relapse, and illicit drug use, and tobacco relapse and methadone dose. Findings will be used to generate empirically based risk indices for smoking cessation failure, which can be used by clinicians in designing optimally effective individualized interventions.